Hi from CNN, I'm Madeline Thompson with the five things you need to know for Friday, June 21st.

In its latest decision, the Supreme Court has upheld a federal law that bars guns for domestic abusers.

The High Court rejected an argument by gun rights groups

that the prohibition violated the Second Amendment.

CNN's Paula Reed explains the significance.

This is a big win for those who want to limit people from having guns if they pose a threat to others.

In the oral arguments, the solicitor general pointed to the fact that someone who lives with someone and they are a survivor of domestic violence from that individual is five times more likely to die if that person has a gun.

And of course there was a dissent from Justice Clarence Thomas.

He writes, quote, the court and the government do not point to a single historical law,

revoking a citizen's Second Amendment right based on possible interpersonal violence.

Heat advisories, watches, and warnings have been extended into the weekend for much of the

Northeastern U.S. according to the National Weather Service.

So let's talk about what these scorching temperatures can do to the human body.

CNN's Dr. Sanjay Gupta has the science and some warning signs to look out for.

Studies have shown that heat is in fact the deadliest of natural

disasters, particularly for those who are more at risk. When you get hot there's a

small region in your brain called the hypophalanous that sends a message to your sweat glands to start the cooling process.

Now if you lose too much water or salt through excessive sweating, this can actually cause heat exhaustion.

Look out for these symptoms. Also try to cool

your body down by moving to a cool place if possible or taking a cool shower. If

symptoms get worse, like you start vomiting or confusion develops, you should seek medical attention.

Heat exhaustion is often confused with heat stroke, but this is a much more serious condition.

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